With radiotherapy, there is a need to position the patient in the same position, when obtaining diagnostic images and each of the subsequent times when radiation is applied to the patient's body. Present systems for positioning patients include various forms of systems for placing markers on the patient to enable the patient to be realigned for different applications of therapy. These systems are problematic in terms of aspects such as repeatability.
What is needed is a markerless calibration and measurement system that does not rely on marker placement on the patient to automatically determine breathing measurement regions.